Production and treatment of artificial filaments, threads, ribbons, and the like



Patented Feb. 16, 1937 2,070,584 AND TREATMENT OF ARTI- PRODUCTION FICIAL FILAMENTS, THREADS,

AND THE LIKE PATENT OFFICE,

masons,

Henry Dreyfus, London, England No Drawing. Application May 25, 1933, Serial No. 672,805. In Great Britain June 14, 1932 12 Claims.

creased extension and tensile" strength may be,

obtained. This application is a continuation-inpart of application S. No. 378,684 filed July 16, 1929.

U.' S. Patent No. 1,709,470 describes processes in which cellulose acetate filaments are stretched beyond their elastic limit at any suitable stage of their manufacture, after the artificial silk is in the fully set and finished condition, the stretching being assisted, if desired, by means of assisting agents" which swell the cellulose acetate materials, for example acetone, ethyl alcohol, formaldehyde or glycerine. Again, U. S. application S. No.. 378,684 filed July 16,1929 describes the stretchin of filaments, threads and similar products containing cellulose acetate or other organic esters of cellulose while they are travelling from one point to another, the stretching being facilitated by the action of solvents or swelling agents for the cellulose derivative, and U. S. ,application S. No. 403,140 filed October 28, 1929, describes the advantages obtained by employing solvents in relatively high concentration to assist the stretch.

U. S. application S. No. 573,424 filed November 6, 1931, describes a process for improving the properties of filaments, threads, yarns, ribbons and the like containing cellulose esters or ethers,

and particularly their tensile strength, in which the materials are softened and then subjected to at least two stages of stretching, the tension beini substantially removed between at least two of th stages, while retaining the plasticity or softness of the products.

Afllthese processes result in the production of filaments and other materials having increased tensile strength, but on the other hand such materials may have a relatively low extension. A method of obtaining materials which have both good tensile strength and also a satisfactory extension is described in U. S. application S. No. 611,240 filed May 13, 1932, according to which artificial filaments, yarns, ribbons and the like made of or containing organic derivatives of cellulose, and particularly wet spun products or dry spun products which have been submitted to a stretching operation, are treated with shrinking agents.

These specifications, therefore, relate either to processes for improving the tensile strength of artificial filaments and other materials containing organic derivatives of cellulose by stretching them, or to improving the extension of artificial filaments and the like by a shrinking operation.

I have now discovered that the properties of artificial filaments, threads, yarns, ribbons, foils and the like made of. or containing organic derivatives of cellulose, and particularly their extensibility and tensile strength, may be improved by treating them with shrinking agents in the absence of tension suflicient to stretch them and then subjecting them to a stretching operation. Preferably treatment with the shrinking agents is carried out so that the filaments and the like are not subjected to any tension, or at least only a moderate tension,- but if a relatively high tension is applied, the tension should be subsequently decreased or removed, so that shrinkage or further shrinkage is possible.

The invention is especially of value in relation to the treatment of artificial materials made of or containing cellulose acetate and it will there fore be described with particular reference thereto. Its appli ation, however, is by no means limited to su n materials and it is also of value in connection-with the treatment of materials containing other organic esters or mixed esters of cellulose, for example cellulose formate, propionate, butyrate and nitroacetate, methyl, ethyl, propyl, butyl and benzyl cellulose and other cellulose ethers or mixed ethe s, and mixed cellulose ether-esters, for example, ethyl cellulose acetate and oxyethyl cellulose acetate.

The process of the present invention may be carried out as a separate operation distinct from the production of the materials, as, for example. in a bobbin to bobbin treatment or with skeins, hanks or other packages, or it may be applied continuously with the production of the artificial materials wet or dry processes.

When the invention is applied to the treatment 40 of artificial filaments, yarns and the like in hank form, the apparatus described in U. S. application S. No. 573,424 in connection with the application of stretch to such materials, or a modification thereof, may very conveniently be employed. This apparatus consists of a relatively long bath which, for the purposes of the present invention, will contain the shrinking agent, and which may be lined-with a suitable material which is resistant to the action of such agent. A long screw fitted with a hand wheel or other suitable drive is arranged longitudinally along the top of the bath in which two rollers carried on suitable supports are posiany suitable means may of course be employed whereby the hanks are allowed to shrink by the desired amount. For example, hanks may be placed on the rollers and their distance apart adjusted so that the hanks are able to shrink to a certain definite and predetermined extent under the influence of the shrinking agent contained in the bath, or alternatively the roller which is not carried on the screw maybe free to move longitudinally along the bath, so that the hanks can shrink freely, the shrinking of the yarn itself drawing the rollers nearer together. When sufficient shrinkage has taken place, stretching may be carried out in the same apparatus, as is described in U. S; application S. No. 573,424 referred to above. Thus the position of the free roller may be fixed, and the hanks stretched by rotating the screw, and thus causing the roller carried thereon to move away from the free roller. shrinking may be the same as that employed for the softening process, or, if desired, it may be' different, in which case, on completion of shrinking, the shrinking agent is removed and the bath then filled with the softening agent which it is desired to employ. Alternatively of course the stretching process may be carried out in any other suitable manner, for example as described in U. S. Patent No. 1,709,470.

Other methods by which shrinking may be carried out upon the materials in package form include the use of resilient bobbins, swifts or supports and of loosely wound packages, and in this connection, as well as in connection with the shrinking of materials during their travel from one point to another, referred to in greater detail below, reference is made broadly to the methods described ,in U. S. application S. No. 611,240. 1

Alternatively the shrinking operation may be carried out upon the artificial materials during the course of their travel from one point to another, as for example in a bobbin to bobbin winding operation or in the course of their production by dry or wet spinning processes. Thus, arti ficial filaments proceeding from a bobbin or other suitable package or from a dry or wet spinning apparatus may be passed around a positively driven roller, through a suitable shrinking bath and then wound on a second roller positively driven at a peripheral speed less than that of the first roller, so that the desired shrinking can take place. Alternatively nip rollers may be employed and/or the shrinking bath may itself be caused to flow in a direction counter to that of the travel of the artificial filaments or other materials so as to assist shrinkage. The use of liquid baths in motion for the purpose of restricting the tension applied to the artificial filaments is described in U. S. application S. No. 593,859 filed February 18, 1932, and the principles described therein may be applied to the present invention.

While the shrinking agentsto be employed according to the present invention are preferably The agent used to bring about the applied by passing the materials through baths containing the agents, yet the invention is not limited to such methods. For instance, the

shrinking agents may be applied in the vapour of the gases may be employed to assist the shrinking, using, for example, the principles disclosed in U. S. application S. No. 590,828 filed February 4, 1932.

Not only may the shrinking operation be carried out continuously with the production of the artificial materials by passing them from the coagulating bath or evaporative medium into a suit-' able shrinking bath, but, if desired, shrinkage may also take place simultaneously or substantially simultaneously, with the formation of the materials. For example, in the case of wet spinning, a positively driven guide roller or nip rollers may be suitably positioned in the coagulating bath and rotated at a peripheral speed less than that at which the artificial filaments and the like are extruded from the spinning orifices and thus by the use of suitable coagulating baths shrinkage may take place in the bath itself. If desired, a draw roller rotating at a-peripheral speed substantially equal to that of extrusion may be positioned between the. jets and the above mentioned guide or nip rollers. Suitable baths for this purpose are those containing solvents or latent solvents for the cellulose derivative as described in U. S. Patents Nos. 1,465,994 and 1,467,493, and U. S. applications S. Nos. 402,785 filed October 26, 1929, and 437,423 filed March 20, 1930, or coagulating baths containing the shrinking agents v position either inside or outside the cell, and if desired an intermediate roller, as described above a in relation to wet-spinning, may also be employed.

An outlet for the atmosphere containing shrinking agent and an inlet for the main evaporative atmosphere may be provided at points between the inlet for shrinking agent, which will be remote from the jets and the outlet for the main evapqr rative atmosphere in the vicinity of the jets.

Amongst suitable shrinking agents for use in accordance with the present invention may be mentioned acetic acid, formic acid, lactic acid,

diacetone alcohol, acetone, aliphatic alcohols, e.

g. ethyl alcohol, mono-and di-ethers or esters or ether-esters of olefine or polyolefine glycols, for example monoand di-ethyl ethers of ethylene glycol, glycol mono-acetata nethyl glycol monoacetate, dioxane and other cyclic ethers, for example methylene ethylene oxide, the mono '-j methyl and ethyl ethers of propylene glycol and the mono ethyl ethers of diethylene glycol, phenols, mono, diand tri-acetins, dichlorethylene, ethyl lactate, diethyl tartrate and other substances or solutions or' mixtures having swelling, solvent or latent solvent action upon the ce1lu-' paratively small proportions of an alcohol or certain other liquids,-become capable of dissolving cellulose acetates, and they are usually referred to as latent solvents for cellulose derivatives. Such latent solvents are particularly advantageous for use in accordance with the present invention, but they are preferably not employed in admixture with alcohols or other agents which are capable of converting them into true solvents, but either alone or in admixture with diluents or substances having little or no solvent or swelling or similar acting substances, proportions should be chosen so that a true solvent mixture is not formed.

As suitable diluents for use in connection with the present invention may be mentioned water, glycerol, glycol or other hydroxy' compounds, though preferably water-immiscible liquids are employed. Examples of such liquids are benzene, toluene and other cyclic hydrocarbons, benzene, kerosene, carbon-tetrachloride, petrol ether, trichlorethylene, perchlorethylene and. other chlorinated or halogenated compounds which are inert or relatively inert towards the cellulose derivative. High boiling diluents, for example tetrahydro-naphthalene and decahydronaphthalene,'may also be employed. I

As is described in U. 3.. application S. No. 611,240, very considerable shrinkages may be produced in the absence of tension by treatment of artificial materials with pure methylene chloride, chloroform, tetrachlorethane or similar latent solvents, and since, according to the present invention, the materials are to be subsequently stretched, a higher degree of shrinkage is in general found desirable than when shrinking follows stretching as in the process of the above specification. Thus, the shrinkage produced according to the present invention may be of the order 15 to 25 or 35%, or even more. Any desired restriction of the shrinkage may be effected by controlling the concentration of the shrinking agent, the time of treatment and/or by carrying out the process under sufficient tension to prevent more than the desired shrinkage. Thus when using a mixture of methylene chloride and benzene in a proportion of :50 by volume, with artificial materials obtained from commercial acetone-soluble cellulose acetate, the process may be carried out so that a shrinkage of 25-30% is effected.

Stretching of the materials after shrinking may be carried out either immediately or after a lapse of time. Preferably however the stretching process is combined with theshrinking process, the

whole forming a continuous operation.

According to the. present invention, the agent employed in effecting shrinkage may be relied upon to soften the materials sufficiently for stretching, or the materials may be treated with further quantities of the same or a different agent. Alternatively, the agent employed for producing shrinkage may be partially or completely removed, the materials being then treated with a softening agent, which in this case also may be the same as or different from that employed to efiect, shrinkage, and stretched.

Thus hanks which have been shrunk in the their travel from one point to another may be carried from the shrinking bath into another bath in which they are stretched, either in a single stage, as is described in U. S. application S. No. 378,684, or in two or more stages, as described in U. S. application S. No. 573,424. Moreover the shrinking and stretching may take place in the same bath, e. g. by passing the filaments or threads first round a roller rotating at a suitable speed either before or upon their entrance into the bath, then round another rotating at a smaller peripheral speed to allow of shrinkage, and then cround one or more rotating at increasingly higher speeds in order to produce the desired stretch. If desired, a rest period may be arranged by rotating two or more successive rollers at the same peripheral speed so that during this portion of October 20, 1932.

Again, filaments and the like which have been subjected to a shrinking operation may issue from the bath in a suificiently softened state to be subjected to the stretching operation without further treatment, particularly if relatively non-volatile shrinking agents are employed, or they may be maintained in or brought to a sufilciently plastic condition merely by spraying, contact with wicks or rollers impregnatedwith the softening agent, or in any suitable manner.

n The agents employed to promote shrinkage or allow of stretching are preferably removed on the completion'of the operation, for example byevaporation in the case-of relatively volatile agents or by a suitable bath treatment. Removal of the agent or agents may be carried out in a single operation on completion of the stretching process, e. g. by washing with solutions of the softening agent in successively decreasing concentrations,

or the shrinking agent may, if desired, be removed before stretching-takes place. Ingeneral, it will be necessary in such cases to assist stretching by treatment of the materials with softening agents. If desired, the softening bath or a portion thereof may be diluted and employed for washing the materials, as described in U. S. application S. No.

desired, be applied to 'a warp. of threads from a suitable creelor beam,.the warp being carried,

e. g. between nip rollers or draw rollers suitably drivenso as to allow of a shrinkage.

Thus a warp of threads may be carried by means of draw rollers through a shrinking bath, the peripheral speeds of the rollers being suitably adjusted to allow of the desired shrinkage, and then in contact with further rollers, either in the same bath or forming part of a separate piece of apparatus, for the purpose of stretching them. If desired, one or more intermediate rollers maybe employed in order toallow of a rest period between shrinking and stretching.

The process may also be applied, if desired, to mixed yarns and the like, for example, yarns containing filaments or threads of an organic derivative of cellulose together with filaments or threads of natural textile materials, for example, cotton, wool, pure silk and the like, and special effects may thus be obtained.

Various methods of carrying out the invention have -been described above, but it is of course evident that the invention is by no means limited thereto, but comprises broadly the treatment of artificial filaments, threads, yarns, ribbons and the like containing organic derivatives of cellulose with shrinking agents, so as ,to bring about shrinkage, combined with a subsequent stretching process, in order to obtain products having an improved extensibility and tensile strength.

The following examples illustrate methods of carrying out the invention but it must be clearly understood that they are not to be considered as limiting it in any way.

Example 1 roller rotating at a lower peripheral speed so that a shrinkage of the order 15-20% may take place. 'From this roller the threads pass through a reed to a third roller rotating at a peripheral speed of 15-20 metres per minute, and thence out of the bath to washing, drying and winding devices. The agent used in the bath for both the shrinking and stretching stages is a solution consisting of methylene chloride and 35% benzene- I Example 2 Cellulose acetate yarn in cake form is immersed in ashrinking agent consisting of ethylacetate and 20% toluene for a period of 5-10 minutes. The cake is then removed and the shrinking agent is then driven off, e. g. by 7 means of a current of warm air. The thread is thenled from the cake (which is carried on a suitable support) to a feed roller which is fixed in a bath and which rotates. at a peripheralspeed of 5-6. metres per minute. The roller is immersed in a softening agent consisting of a 45-50% aqueous solution of dioxane. From the first roller the threads pass to a second roller rotating at a peripheral speed of 20-25 metres per' minute so that a stretch of about 400% is obtained. The threads then pass from the bath to washing, drying and winding devices.

Example 3 A number of cellulose acetate threads are I shrunk and stretched as in Example 1, except with shrinking agents under such conditions that shrinkage occurs to the extent of at least 15% of v the original length and subsequently stretching the materials beyond their original length to increase their tenacity.

2., Process for the manufacture ofartificial filaments, threads, yarns, ribbons, foils and like materials containing cellulose acetate, which comprises treating the materials with shrinking agents under such conditions that shrinkage occurs to the extent of at least 15% of the original length, and subsequently stretching the materials to a length at least of the order of 200% of their original length to increase their tenacity.

3. Process for the manufacture of artificial filaments, threads, yarns, ribbons, foils and like materials containing organic derivatives of cellulose, which comprises treating the materials with shrinking agents under such conditions that shrinkage of the order of 20 to 25% occurs, and subsequently stretching the materials to a length at least of the order of 200% of their original length to increase their tenacity.

4. Process for -the manufacture of artificial filaments, threads, yarns, ribbons, foils and like materials containing cellulose acetate, which comprises treating the materials during their travel from one point to another with shrinking agents under such conditions that shrinkage of the order of 20 to 25% occurs, and subsequently stretching the materials beyond their original length to increase their tenacity.

5. Process for the manufacture of artificial filaments, threads, yarns, ribbons, foils and like materials containing organic derivatives of cellulose, which comprises treating the materials with latent solvents for the organic derivatives of cellulose under such conditions that shrinkage occurs to the extent of at least 15% of the original length, and subsequently stretching the materials beyond their original length to increase their tenacity.

6. Process for the manufacture of artificial filaments, threads, yarns, ribbons, foils and like materials containing organic derivatives of cellulose, which comprises treating the materials with latent solvents under such conditions that shrinkage of the order of 20 to 25% occurs, and subsequently stretching the materials to a length at least of the order of 200% of their original length to increase their tenacity.

'7. Process for the manufacture of artificial filaments, threads, yarns, ribbons, foils and like materials containing cellulose acetate, which comprises treating the materials with latent solvents selected from the group consisting of ethylene chloride, chloroform, tetrachlorethane and ethyl acetate, under such conditions that shrinkage of the order of 20 to 25% occurs, and subsequently stretching the materials beyond. their original length to increase their tenacity.

materials containing cellulose acetate, which comprises treating the materials with methylene chloride under suchconditions that shrinkage of the order of 20 to 25% occurs, and subsequently stretching the materials to a length at least of the order of 200% of their original length to increase their tenacity.

9. PrOcess for the manufacture of artificial threads, yarns, ribbons, foils and like materials containing cellulose acetate, which comprises as a continuous operation treating the materials with latent solvents selected from the group consisting of ethylene chloride, chloroform, tetrachlorethane and ethyl acetate, under such conditionsthat shrinkage of the order of 20 to 25% occurs, and subsequently stretching the materials beyond their original length to increase their tenacity.

10. Process for the manufacture of artificial threads, yarns, ribbons, foils and like materials containing cellulose acetate, which comprises as a continuous operation treating the materials with methylene chloride under such conditions that shrinkage of the order of 20 to 25% occurs,

. and subsequently stretching the materials beyond their original length to increase their tenacity.

11. Process for the manufacture of artificial threads, yarns, ribbons, foils and like materials containing cellulose acetate, which comprises as a continuous operation treating the materials with methylene chloride under such conditions that shrinkage of the order of 20 to 25% occurs, and subsequently stretching the materials beyond their original length to increase their tetheir original length and then stretching the materials to a length greater than their original length along a further part of their path through the bath to increase their tenacity.

HENRY DREYFUS. 

